The present invention relates to ribbons for orienting weapons in flight, and in particular, to a ribbon formed into a flexible loop for orienting a weapon body.
Known grenade submunitions can be ejected in groups from artillery shells, missiles, rockets etc. Such known grenades employ at their aft end a looped cloth ribbon attached at the fuze of the grenade. Also, banner stabilizers are shown in U.S. Pat. No. 4,209,151.
Once a grenade, for instance in-flight and separated from the launch vehicle, the looped ribbon quickly decelerates the grenade from its initial speed. This initial speed may be in the range of 300 to 1200 feet per second, although other speeds may be experienced for different types of launch vehicles or other weapons. The rapid deceleration causes the grenade to fall vertically, with the ribbon trailing vertically behind. This effect tends to keep the grenades in a desirable group pattern and also causes the grenade to strike a ground target nose first, which orientation may be necessary to reliably detonate the grenade.
If the grenades are initially released from an artillery shell, the high spin rate of the shell causes similar spinning of the grenades. The ribbon, however, reduces the tendency of the grenade to spin. Spin reduction is desirable because spinning adversely affects the dynamics of a shaped charge that may be contained in the grenade. Thus, when the grenade separates from the shell, the ribbon dampens the spinning and simultaneously provides the torque needed to unscrew the firing pin spindle and thereby arm the fuze.
Unscrewing this firing pin spindle can be difficult if the grenade is not initially spinning. For missile launched applications, the drag force in conjunction with the vibration produced by the flapping ribbon must unscrew the firing pin. This method of arming the fuze has proven unreliable and failure can result from small changes in the torque resistance that must be overcome to unthread the arming screw.
Accordingly, there is a need for an improved device for creating the drag necessary to orient a weapon such as a grenade in flight, and also to arm or otherwise operate a fuze to allow detonation.